Don’t let the naysayers get you down. I’m not much of a mall person, but for one day to just immerse yourself in it, it can be pretty enjoyable. Indulge the female gatherer (not hunter) side of your shopping persona. Just walk around looking at what catches your eye, and buy whatever fits your budget and makes you happy. Pace yourself, rest for a few and enjoy a coffee or a snack when you feel tired. If your hubby will be with you and is not likely to enjoy this approach, arrange a separate activity for him–maybe he goes to a movie or something.
There are tons of great parks in the Twin Cities. Two I would recommend are Lake Calhoun and Minnehaha Park. There are also two zoos in the area, Como Park in St. Paul and The Minnesota Zoo in Apple Valley. They are both nice, with the Minnesota Zoo more of a modern, natural habitat type.
There are also good museums, especially the Walker Art Museum in Minneapolis and the Science Museum in St. Paul. A historic site in the area, Fort Snelling, is also an area you might like to visit.
Enjoy your trip!